Fork lift trucks



May 23, i951 C. K. FITCH FORK LIFT TRUCKS Filed May 22, 1958 Ffg. f

2 Sheets-Sheet l May 23, 1951 c; K. FITCH 2,985,328

FORK LIFT TRUCKS Filed May 22, 1958 2 Sheets-Sheet 2 Patented May 23, 1961 FORK L11-T TRUCKS Clifford Kingsbury Fitch, Kingsbury Works Bridge Road, Haywards Heath, England Filed May 22, 1958, Ser. No. 737,003

3 Claims. (Cl. 214731) tion, which arms or platforms may either project from the front, rear or side of the vehicle.

According to this invention, a fork lift truck of the kind referred to is characterised in that said lifting arms or platform are so mounted on the lifting head as to be adjustable towards and away from the truck, for example, where the lifting head is arranged in front of the vehicle the said lifting arms or platform are adjustable in a fore and aft direction. 1 Y v The lifting arms or platform are preferably so mounted on the lifting head that they may be adjusted in or out for any position of the head. The arrangement may be such that when the head is in its lowermost position, the arms or platform are retractable beneath the truck.

Power means may be provided for imparting movement to the lifting arms or platform relatively to the lifting head.

@In the case where a number of lifting arms are mounted on the lifting head, said arms are each accommodated in a gudeway extending transversely to the lifting head and projecting therefrom towards the body of the truck.

In such an arrangement, each arm may be provided with a rack extending along the length thereof and the motor driven pinion is arranged to engage each rack.

Each lifting arm in addition to being mounted on the lifting head so as to be movable in a ydirection towards and away from the truck is also movable in a transverse direction along the head. Thus, in the case where four lifting armsare provided, they may be so adjusted that two of them can be arranged to engage the front wheels of a vehicle and the other two to engage the rear wheels of the vehicle. For example, guides for said arms, may be mounted on the laterally movable parts attached to the plungers of the hydraulic rams whereby relative axial movement is imparted to said arms.

The following is a description of two embodiments of the invention as applied to a fork lift truck for parking motor vehicles by lifting them on to superposed supporting platforms reference being made to the accompanying drawings in which:

Figure 1 is a plan view of the mechanism for attachment to the lifting head of the truck embodying a means for moving the fork arms laterally and independently and also, for moving the arms towards and away from the truck.

Figure 2 is a front elevation of the mechanism for imparting fore and aft movement to one of the arms which is shown in section,

Figure 3 is a side elevation of the arrangement shown in Figure 2,

Figure 4 is a diagrammatic plan view of one of the fork arms and its support showing an alternative form of drive for the arm, and

Figure 5 is a diagrammatic side elevation of the truck showing the position of the fork arms in a retracted position.

Referring to Figures l and 5 and the main body 10 of the mechanism is arranged to be secured to the lifting head 9 of the truck 8. The main body is provided with two hydraulic rams mounted one above lthe other (the cylinder 7 of one of them appearing in Figure 1) and each ram being provided with a plunger 11, two plungers extending on opposite sides of the head. Each plunger has attached to itsl outer end a yoke piece 12. This yoke piece 12 has iixed to it another hydraulic ram 13 at a lower level than the plunger 11 and itself having a plunger 14 connected to a second yoke piece 15. Fixed to, or slung from each of the yoke pieces 12 and 15 are two plates 16 and 17 which as will be seen from Figure 3 are L-shaped in contour and are secured together by a number of cross members 18. The bottom portions of all of the L-shaped plates are disposed at the same level whereas the upwardly extending portions of those L-shaped platestwhich are attached to the yoke pieces 12 are disposed at a higher level than those L-shaped plates attached to the yoke pieces 15. A fork arm 20 is arranged to extend between the plates of each pair and has formed on opposite sides thereof with longitudinally extending grooves 21, 22 in which are located a number of rollers 23, 24 having spindles 25, 26 secured in the plates 16 and 17. By these means when the lifting head is in its lowerposition the fork arms may be retracted so that the centre ones lie completely or nearly completely beneath the chassis of the fork lift truck between the wheels lwhile the outer ones flank the wheels. Secured to one side face of each fork arm is a rack 27 which is engaged by a pinion 2S a part of which extends through a hole formed in the plate 17 and which is mounted on a spindle 29 carried by bearings 30 on the outer face of the plate 17. A protecting plate 311 is secured between the plates l16 and 17 over the rack where it engages the pinion so as to prevent the teeth from becoming damaged by extraneous objects.

Secured to the spindle 29 between the bearings 30 is a' Worm wheel 32 which is engaged by a worm 33 xed to one part 34 of a telescopic driving spindle, and worm wheel 32 projects through a hole 35 in the plate 17. Another part 36 of the telescopic driving spindle in which the part 34 is slidably keyed has slidably keyed to it another worm 33 which rotates a worm wheel 32 associated with gearing for actuating another of the fork arms 20. This part 36 of the telescopic driving spindle has fixed to it a worm wheel 37 driven by a Worm, not shown, rotated by a motor 38 mounted on the main body part 10.' Thus, when the motor 38 is energised all the fork arms 20 are moved towards or away from the truck simultaneously the fork arms can be moved towards and away from one another by the operation of said rams 11 and 13. The layout is repeated on the other side of the body 10.

Instead of providing one motor for operating all the fork arms each pair of plates 16 and 17 may have mounted upon it an electric motor 40 shown diagrammatically in Figure 4 the spindle 41 of which is provided with a skew bevel wheel 42 which engages a suitable rack 43 on the side of each arm, otherwise the arm is mounted in a similar manner to that described with reference to Figures 2 and 3.

It will be appreciated that when such a truck is employed for lifting cars onto any of a number of sets of superimposed platforms, the gangway between adjacent sets of platforms can be considerably narrower than the case in which the fork arms of the trucks permanently project away from the truck. In the case where a car is to be parked, it is driven into the gangway alongside one of the sets of the racks, the fork lift truck with its lifting arms retracted, is then ,rnanoeuvred` so vthat the front of the truck is closely adjacent the side of the vehicle, the arms are then projected forwardly so that two of the arms flank the front wheels and the other two arms flank the rear wheels, the hydraulic mechanism is then actuated so that the arms engage the wheels, the truck is then manoeuvred to a position beneath an empty space on a platform, the lifting head is then raised and the truck manoeuvred so that the vehicle is brought over the empty space whereupon the lifting head is lowered so that the arms are clear of the wheels, and either the vehicle is moved away from the rack or platform and the head then lowered, or the arms are retracted relatively to the lifting head whereupon the head is lowered. Y

It will be appreciated that various modications may be made to details ofrconstruction without departing from the scope f the invention for example instead of providing two fork arms in each side of the main body of the device for attachment to the lifting head, a single lifting platform may be provided on each side which is shiftable laterally and also movable in a direction towards and away from the truck. Y

I claim: t Y

l. A fork lift truck for raisingand lowering four wheeled vehicles comprising a lifting head, twoV hydraulic rams at different levels mounted on said head having plungers movable laterally with respect to said head on opposite sides thereof, each of which plungers has fixed thereto, a yoke piece to which is attached a further hydraulic ram cylinder disposed at a different level to the plunger which carries the yoke piece which further hydraulic ram has a plunger movable towards and away from the head, each of which four plungers has secured thereto a mounting for a fork lifting arm constraining it to move in a substantially horizontal direction transversely to the movement of the plunger and power means for effecting said transverse movement of said fork lifting arms.

2. A fork lift truck according to claim l wherein the power means for effecting the horizontal movement of said lifting armsl transverselyto the movement of the arms towards and away from one another comprise an electric motor mounted Dn each of said mountings and driving a pinion which engages a rack extending along the lifting arm. Y

3. A fork lift truck according to claim l wherein the power means for effecting horizontal movement of said lifting arms transversely to the movement of the arms towards and away from one another comprises an electric-motor mounted on said head and driving a telescopic spindle and wherein each said arm has a rack extending along it which ,is engaged by arpinion mounted on the mounting for said arm, and which is driven by a gearwheel on a part of said telescopic arm.

References Cited in the le of this patent UNITED STATES PATENTS 2,122,992v Pride `uly 5, 1938 2,598,865 lTurner June 3, 1,952 2,775,359 Carpenter Dec. 25, 1,956 2,807,383 Scheltens A Sept. 24, 1957 FOREIGN PATENTS v1,093,565 France t-, V May 6, 1955 

